diff --git a/requirements.txt b/requirements.txt
index b7fdc6d..71cfb4a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -31,7 +31,7 @@ Keras==2.2.0
 Keras-Applications==1.0.2
 Keras-Preprocessing==1.0.1
 louis==1.3
-lxml==3.5.0
+lxml==4.9.1
 Markdown==2.6.11
 MarkupSafe==1.0
 mistune==0.8.3